The present invention relates to a hinge assembly for monitor, and more particularly to a hinge assembly for monitor in which a highly pressure-resistant and wear-resistant separate washer is disposed between any two adjacent components on two pivot shafts of the hinge assembly before such components are tightly locked together to produce a torque selected depending on the load of the monitor. The separate washers form separating layers and provide good friction surfaces among the components on the pivot shafts, enabling the hinge assembly to have prolonged service life without the need of anti-rust grease or lubricant.
Hinge assemblies have been widely used with monitors, including monitors for general desktop computers and notebook computers, so that monitors could be easily adjusted to a desired angular position relative to users. An important requirement for such hinge assemblies is they must be able to keep the monitors in a stationary state after the monitors have been adjusted to a desired inclination. That is, a monitor would not freely turn downward at the hinge assembly due to its own weight. Moreover, the hinge assembly must be functionally endurable. In the case of a notebook computer, a monitor thereof might be repeatedly turned open, adjusted to a desired inclination, and closed everyday. That is, the hinge assembly of the monitor of the notebook computer works many times everyday. The hinge assembly must be able to support the monitor so that the monitor may stay at a desired inclination without xe2x80x9cnoddingxe2x80x9d. As a basic design requirement, the hinge assembly for the monitor of a notebook computer having a service life about three to five years must be able to endure at least 10,000 cycles of turning during this term and must maintain its basic performance in each turning. In general endurance tests of the hinge assemblies for monitors, each hinge assembly is caused to swing by 20 degrees and total 10,000 to 30,000 cycles of swing are done, depending on an actual requirement in the quality of a product. The performance of the tested hinge assembly is checked every 1,000 cycles of swing thereof.
Although most hinge assemblies for monitors known in the art are based on similar design principles, that is, employing a frictional force between rotating parts, they are, however, different in their structures. Most of the known hinge assemblies for monitors are exclusively designed for use with a specific monitor. That is, each hinge assembly for monitor, due to its designed precision, has a structure and specification only suitable for a certain specific type of monitor. When a torque is changed due to, for example, changes in the load of monitor or the arm of force of brackets of the hinge assembly, the hinge assembly would no longer maintain its basic performance. FIGS. 1 and 2 illustrate two conventional hinge assemblies for monitor that represent the currently most widely employed designs in the markets. The first conventional hinge assembly for monitor shown in FIG. 1 includes a high-precision spring that is designed and manufactured at very high precision standard and therefore requires high manufacturing cost. However, such precision spring is not adjustable with changes in the torque of the monitor. Such precision spring also has short usable life. It is subject to quick wearing and loses its function after a high limit of working cycles thereof has been reached. The second conventional hinge assembly for monitor shown in FIG. 2 has a pivot shaft providing a preset frictional force decided through high precision design. Rotating parts on the pivot shaft are then firmly riveted together with a desired torque without the need of a precision spring. The second conventional hinge assembly for monitor, as the first type, is subject to quick wearing. Moreover, the second type of hinge assembly requires frequent application of anti-rust grease or lubricant to ensure its ability of normal operation, resulting in inconveniences in assembling thereof. It is therefore desirable to develop a hinge assembly for monitor that eliminates the drawbacks existing in the conventional products.
A primary object of the present invention is to provide a hinge assembly for monitor, in which separate washers made of highly pressure-resistant and wear-resistant materials and having a selected thickness are disposed between adjacent components on pivot shafts of the hinge assembly to form separating layers and provide good friction surfaces among the components on the pivot shafts, enabling the hinge assembly to have prolonged service life without the need of anti-rust grease or lubricant.
Another object of the present invention is to provide a hinge assembly for monitor, in which separate washers made of highly pressure-resistant and wear-resistant materials and having a selected thickness are disposed between adjacent components on pivot shafts of the hinge assembly, and the separate washers and other components on the pivot shafts are tightened together with a torque decided by the load of monitor. By locking the components on the pivot shafts to different degrees of tightness, the hinge assembly may be applied to monitors of different torques. Whereby, the hinge assembly could be manufactured and used in a cost effective manner.